Ankle exerciser



FIG. 1 is a perspective view showing the top and one side of the design, with the opposite side surface being the mirror image of that shown;

FIG. 2 is a side elevational view, with the opposite side being the mirror image;

FIG. 3 is a top plan view;

FIG. 4 is a bottom plan view;

FIG. 5 is a front view; and,

FIG. 6 is a rear view of the design. 

The ornamental design for an ankle exerciser, as shown and described. 